If there was any doubt in your mind as to Microsoft's priorities regarding its two Windows client available concomitantly, Windows Vista and Windows XP, the race to bring the service packs for the two operating systems to the finish line should offer some indications as to the company's strategy. Although both Vista SP1 and XP SP3 debuted into beta stages almost simultaneously in mid-2008, and went through development milestones at the same pace, Vista Service Pack 1 was finalized almost two months ahead of XP Service Pack 3. Additionally, the releasing to manufacturing of XP SP3 delivered further proof that the main focus is on Vista.

With XP SP3 having RTM'd on April 21, 2008, Chris Keroack, Windows XP SP3 release manager revealed that the service pack will be delivered through Windows Update and the Download Center on April 29, days ahead of the launch date for the Microsoft Developer Network and TechNet subscribers.

"To meet high customer demand for Windows Vista Service Pack 1, we have optimized available bandwidth and prioritized MSDN/TechNet delivery channels for Windows Vista SP1 downloads in all Windows languages. Once we have satisfied this demand, we will roll out Windows XP SP3 via MSDN/TechNet," a Microsoft spokesperson said to CRN.

It is useless to say that MSDN and TechNet subscribers were less happy with the Redmond company's decision to make them wait until May 2, according to the leaked timetable for the delivery of XP SP3 (via Nick MacKechnie, Senior Technical Account Manager at Microsoft New Zealand). The pressure from MSDN and TechNet members contributed to changing Microsoft's mind, and as a direct consequence Windows XP SP3 became available for download. But only thought MSDN and TechNet, and only when customer demand for XP SP3 proved to overtake that for Vista SP1.

Update: Windows XP SP3 RTM Build 5512 available for download here.